Elastomer composition containing mercaptofunctional silane and process for making same

Abstract

A filled elastomer composition comprises: a) at least one rubber component; b) at least one particulate filler; and, c) at least one mercaptofunctional silane of a particular structure.

1. A filled elastomer composition comprising:
 a) at least one rubber component; 
 b) at least one particulate filler; and, 
 c) at least one mercaptofunctional silane general Formula (1):
   [HSG 1 SiZ θ Z β ] m [HSG 2 SiZ β   3 ] n [HSG 3 SiZ β   2 X] o [[HSG 4 SiZ β X 2 ] p    (1) 
 
 wherein:
 each occurrence of G 1 , G 2 , G 3 , and G 4  is independently a hydrocarbylene group containing from 1 to 30 carbon atoms selected from the group consisting of divalent groups derived by substitution of a hydrogen on alkyl, alkenyl, aryl, or aralkyl or a substituted divalent heterocarbon containing 2 to 30 carbon atoms and one or more etheric oxygen (—O—) and/or sulfur (—S—) atoms; 
 each occurrence of X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, —R, (HO) d-1 G 5 O—, wherein each R is independently selected from the group consisting of hydrogen, straight, cyclic or branched alkyl that can or can not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, wherein each R, other than hydrogen, contains from 1 to 18 carbon atoms, G 5  is independently a hydrocarbylene group of from 2 to 15 carbon atoms or a divalent heterocarbon group of from about 4 to about 15 carbon atoms containing one or more etheric oxygen atoms; 
 each occurrence of Z β , which forms a bridging structure between two silicon atoms, is [—OG 5 (OH) d-2 O—] 0.5 , wherein each occurrence of G 5  is independently selected from the group consisting of a hydrocarbylene group from 2 to 15 carbon atoms and a divalent heterocarbon group of from 4 to 15 carbon atoms containing one or more etheric oxygen atoms; 
 each occurrence of Z θ , which forms a cyclic structure with a silicon atom, is independently given by —OG 5 (OH) d-2 O—, wherein G 5  is independently selected from the group consisting of a hydrocarbylene group of from 2 to 15 carbon atoms or a divalent heterocarbon group of from 4 to 15 carbon atoms containing one or more etheric oxygen atoms; 
 each occurrence of subscripts d, m, n, o and p independently is an integer wherein d is from 2 to 6; m is 0 to 20; n is 0 to 18; o is 0 to 20; and, p is 0 to 20, with the proviso that m+n+o+p is equal to or greater than 2. 
 
 
     
     
       2. The filled elastomer composition of  claim 1  wherein rubber component (a) is at least one member selected from the group consisting of styrene-butadiene rubber, emulsion styrene-butadiene rubber, natural rubber, polybutadiene rubber, ethylene-propylene-diene monomer terpolymer and acrylonitrile-butadiene rubber. 
     
     
       3. The filled elastomer composition of  claim 1  wherein rubber component (a) is at least one member selected from the group consisting of natural cis-1,4-polyisoprene rubber, synthetic cis-1,4-polyisoprene rubber, emulsion polymerization-prepared styrene/butadiene copolymer rubber, organic solution polymerization-prepared styrene/butadiene rubber, 3,4-polyisoprene rubber, isoprene/butadiene rubber, styrene/isoprenelbutadiene terpolymer rubber, cis-1,4-polybutadiene, medium vinyl polybutadiene rubber of about 35 to about 50 percent vinyl content, high vinyl polybutadiene rubber of about 50 to about 75 percent vinyl content, styrene/isoprene copolymer, emulsion polymerization-prepared styrene/butadiene/acrylonitrile terpolymer rubber and butadiene/acrylonitrile copolymer rubber. 
     
     
       4. The filled elastomer composition of  claim 1  wherein rubber component (a) is at least one member selected from the group consisting of emulsion polymerization-derived styreneibutadiene having a bound styrene content of from about 20 to about 28 weight percent styrene or, an emulsion polymerization-derived styrene/butadiene having a bound styrene content of from about 30 to about 45 weight percent and an emulsion polymerization-prepared styrene/butadiene/acrylonitrile terpolymer rubber containing from about 2 to about 40 weight percent bound acrylonitrile. 
     
     
       5. The filled elastomer composition of  claim 1  wherein rubber component (a) is a solution styrene-butadiene rubber having a bound styrene content of from about 5 to about 50 weight percent. 
     
     
       6. The filled elastomer composition of  claim 1  wherein rubber component (a) is a solution styrene-butadiene rubber having a bound styrene content of from about 9 to about 36 weight percent. 
     
     
       7. The filled elastomer composition of  claim 6  wherein rubber component (a) is a solution styrene-butadiene rubber having a bound styrene content of from about 20 to about 30 weight percent. 
     
     
       8. The filled elastomer composition of  claim 1  wherein rubber component(a) is a polybutadiene rubber having a cis-1,4 content of at least about 90 weight percent. 
     
     
       9. The filled elastomer composition of  claim 1  wherein particulate filler (b) is at least one member selected from the group consisting of metal oxide, siliceous material and carbon black. 
     
     
       10. The filled elastomer composition of  claim 9  wherein the metal oxide is at least one member selected from the group consisting of silica, titanium and alumina; and, the siliceous material is at least one member of the group consisting of aluminosilicate, clay and talc. 
     
     
       11. The filled elastomer composition of  claim 10  wherein particulate filler (b) is at least one member selected from the group consisting of mixtures of silica and carbon black and mixtures of silica and alumina. 
     
     
       12. The filled elastomer composition of  claim 1  wherein in mercaptofunctional silane (c):
 each occurrence of G 1 , G 2 , G 3  and G 4  is independently a hydrocarbylene group containing from 1 to 30 carbon atoms derived by substitution of a hydrogen on alkyl, alkenyl, aryl, or aralkyl; 
 each occurrence of Z β , which forms a bridging structure between two silicon atoms, is independently [—O(R 0 CR 0 ) f O—] 0.5 , wherein each occurrence of R 0  is independently given by one of the members for R, and f is from 2 to 15; 
 each occurrence of Z θ , which forms a cyclic structure with a silicon atom, is independently [—O(R 0 CR 0 ) f O—] 0.5 , wherein each occurrence of R 0  is independently given by one of the members for R, and f is 2 to 15; 
 each occurrence of X is independently —OR, wherein each occurrence of R is independently selected from the group consisting of straight, cyclic and branched alkyl, alkenyl, aryl and aralkyl containing up to 18 carbon atoms; and, 
 each occurrence of m, n, o, and p independently is an integer wherein m is from 0 to 20, n is specifically from 0 to 18, o is from 0 to 20, and p is from 0 to 20, with the proviso that m+n+o+p is equal to or greater than 2. 
 
     
     
       13. The filled elastomer composition of  claim 2  wherein in mercaptofunctional silane (c) each occurrence of G 1 , G 2 , G 3  and G 4  is independently a straight or branched chain alkylene group of up to 6 carbon atoms; each occurrence of R 0  is independently hydrogen or a straight or branched chain alkyl group of up to 6 carbon atoms and f is 2 to 4; and, m is 0 to 5, n is 0 to 4, o is 0 to 5 and p is 0 to 5. 
     
     
       14. The filled elastomer composition of  claim 3  wherein in mercaptofunctional silane (c) each occurrence of G 1 , G 2 , G 3  and G 4  is independently 3 carbon atoms, each occurrence of R 0  is independently hydrogen or straight or branched chain alkyl group of 1 to 3 carbon atoms and f is 2 or 3; and, m is 0 or 1, n is 1 or 2, o is 1 or 2 and p is 0 or 1. 
     
     
       15. The filled elastomer composition of  claim 1  wherein in mercaptofunctional silane (c):
 each occurrence of G 1 , G 2 , G 3  and G 4  is independently a group derived by substitution of hydrogen on alkyl, alkenyl, aryl, or aralkyl having up to 30 carbon atoms; 
 each occurrence of X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, R 2 N—, —R, (HO) d-1 G 5 O—, HO(CR 0   2 ) f O—, and HO(CR 0   2 CR 0   2 O) e —, wherein each R is independently selected from the group consisting of hydrogen or straight, cyclic or branched alkyl, alkenyl, aryl, and aralkyl groups of up to 18 carbon atoms; 
 G 5  is independently a hydrocarbylene group of from 2 to 15 carbon atoms or a heterocarbylene group of from 4 to 15 carbon atoms containing one or more etheric oxygen atoms; 
 R 0  is independently given by one of the members for R; 
 each occurrence of Z β , which forms a bridging structure between two silicon atoms, is independently selected from the group consisting of, [—OG 5 (OH) d-2 O—] 0.5 , [—O(CR 0   2 CR 0   2 O) e —] 0.5  and [—O(R 0 CR 0 ) f O—] 0.5 , wherein each occurrence of R 0  is independently given by one of the members listed for R; 
 each occurrence of Z θ , which forms a cyclic structure with a silicon atom, is independently given by —OG 4 (OH) d-2 O—, —O(CR 0   2 CR 0   2 O) e — and —O(R 0 CR 0 ) f O— wherein each occurrence of R 0  is independently given by one of the members for R; and, 
 each occurrence of the subscripts d, e, f, m, n, o and p is independently an integer wherein d is from 2 to 6, e is from 2 to 7, f is from 2 to 15, m is from 0 to 20, n is from 0 to 18, o is from 0 to 20 and, p is from 0 to 20, with the proviso that m+n+o+p is equal to or greater than 2. 
 
     
     
       16. The filled elastomer composition of  claim 5  wherein in mercaptofunctional silane (c) d is 2 to 4, e is 2 to 4, f is 2 to 4, m is 0 to 5, n is 0 to 4, o is 0 to 5 and p is 0 to 5. 
     
     
       17. The filled elastomer composition of  claims 6  wherein in mercaptofunctional silane (c) d is 2, e is 2, f is 3, m is 1 or 2, n is 1 or 2, o is 1 or 2 and p is 0 to 2. 
     
     
       18. The filled elastomer composition of  claim 1  wherein mercaptofunctional silane (c) is at least one member selected from the group consisting of 3-(2-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-5-methyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol; 3-(2-{3-[2-(3-mercapto-propy)-4,4,6-trimethyl-[1,3,2]dixasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-thiol; 3-(2-{3-[2-(3-mercapto-propyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol; 3-({3-[2-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-yloxy]2-methyl-propoxy}-bis-[3-hydroxy-2-methyl-propoxy]-silanyl)-propane-1-thiol; 3-[{3-[{3-bis-(3-hydroxy-2-methyl-propyl)-(3-mercapt-propyl)-silanyloxy]-1-methyl-propoxy}-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propan-1-ol; 3-[[3-((3-hydroxy-3-methyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-1-methyl-propoxy}-silanyloxy)-2-methyl-propoxy-(3-hydroxy-2-methyl-propoxy)-3-mercapto-propyl)-silanyl]-2-methylpropan-1-ol; 3-(2-{3-[2-(3-mercapato-butyl)-[1,3,2]dioxasilinan-2-yloxy]-propoxy}-[1,3,2]dioxasilinan-2-yl)-butane-1-thiol; 3-(2-{3-[2-(3-mercapto-phenyl)-4,4,6-trimethyl-[1,3,2]dixasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-3-benzene-thiol; 3-(2-{3-[2-(3-mercapto-cyclohexyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-cyclohexane-1-thiol; 3-({3-[2-mercapto-methyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-diethoxy]-silanyl)-methane-1-thiol; 3-[{3-[{3-bis-(3-hydroxy-2,2-dimethyl-propyl)-(3-mercapt-propyl)-silanyloxy]-2,2-dimethyl-propoxy}-(3-hydroxy-2,2-dimethyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2,2-dimethyl-propan-1-ol; 3-[[3-((3-hydroxy-3-phenyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-phenyl-[1,3,2]dioxasilinan-2-yloxy]-2-phenyl-1-propoxy}-silanyloxy)-2-phenyl-propoxy-(3-hydroxy-2-phenyl-propoxy)-3-mercapto-propyl)-silanyl]-2-phenylpropan-1-ol; 3-[{3-[(methyl)-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propoxy}-methyl)-(3-mercapto-propyl)-silanyloxy]2-methyl-propan-1-ol. 
     
     
       19. The filled elastomer composition of  claim 1  containing from about 30 to about 98 weight percent of rubber component (a), from about 2 to about 70 weight percent particulate filler (b) and from about 0.2 to about 20 weight percent mercaptofunctional silane (c). 
     
     
       20. The filled elastomer composition of  claim 1  containing from about 50 to about 95 weight percent of rubber component (a), from about 5 to about 50 weight percent particulate filler (b) and from about 0.5 to about 50 weight percent mercaptofunctional silane (c). 
     
     
       21. The filled elastomer composition of  claim 1  containing from about 60 to about 80 weight percent of rubber component (a), from about 20 to about 40 weight percent particulate filler (b) and from about 2 to about 10 weight percent mercaptofunctional silane (c). 
     
     
       22. The filled elastomer composition of  claim 1  further comprising (d) at least one curative; (e) at least one polyhydroxyl-containing compound produced in situ from the hydrolysis of mercaptofunctional silane (a) and/or separately added to the composition; and (f) optionally, at least one accelerator. 
     
     
       23. An article of manufacture comprising at least one component of which is the cured filled elastomer composition of  claim 1 . 
     
     
       24. The article of manufacture of  claim 23  selected from the group consisting of tire, shoe sole, hose, seal, gasket, cable jacket, conveyer belt and power transmission belt. 
     
     
       25. A process for making a filled elastomer composition which comprises:
 a) mixing:
 (i) at least one rubber component, 
 (ii) at least one particulate filler, and 
 (iii) at least one mercaptofunctional silane of Formula (1) of  claim 1 , supra; 
 
 b) optionally mixing:
 (iv) at least one curative and/or 
 (v) at least one accelerator and/or 
 (vi) at least one polyhydroxy-containing compound into the composition resulting from step (a); 
 
 c) optionally molding the composition resulting from step (b); and, 
 d) optionally curing the composition resulting from step (b) and step (c). 
 
     
     
       26. The process of  claim 25  wherein at least a portion of particulate filler (ii) is pretreated with at least a portion of mercaptofunctional silane (iii) prior to their mixture with rubber component (i), the resulting treated filler being mixed with rubber component together with, or in the absence of, additional particulate filler (ii) and/or mercapto functional silane (iii). 
     
     
       27. The process of  claim 26  wherein treated filler contains mercaptofunctional silane (iii) in admixture therewith and/or chemically bonded thereto. 
     
     
       28. A process for making a rubber composition which comprises:
 a) thermomechanically mixing, in at least one preparatory mixing operation, to a temperature of from about 140° C. to about 180° C., for a total mixing time of from about 1 to about 20 minutes for such mixing operation(s):
 i) about 100 parts by weight of at least one sulfur vulcanizable rubber selected from the group consisting of conjugated diene homopolymers and copolymers and copolymers of at least one conjugated diene and aromatic vinyl compound, 
 ii) from about 5 to about 100 parts by weight of particulate filler, wherein the filler preferably contains from 0 to about 85 weight percent carbon black, and 
 iii) from about 0.05 to about 20 parts by weight filler of at least one mercaptofunctional silane of Formula (1) of  claim 1 ; 
 
 b) blending the mixture from step (a), in a final thermomechanical mixing step at a temperature of from about 50° C. to about 130° C. for a time sufficient to blend the rubber, and a curing agent at 0 to 5 parts by weight; and, 
 c) optionally curing said mixture at a temperature in the range of from about 130 to about 200° C. for a period of from about 5 to about 60 minutes. 
 
     
     
       29. The process of  claim 28  wherein in step (b), at least one polyhydroxy-containing compound is also blended with the mixture from step (a).